Lemberg
hydroxymethyl-j-methylocta-z,y-dienes



`une 28, 1966 s. LEMBERG HYDROXYMETHYL-Z-METHYLOCTA-Z 7DIENES Filed July 17, 1961 ewa ooh

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omb oom com mgg *i Wit/57% United States Patent O 3,258,497 HYDROXYMETHY L-Z-METHYLO CTA-2 ,7 -DIENES Seymour Lemberg, Elizabeth, NJ., assgnor to International Flavors & Fragrances Inc., New York, N.Y., a corporation of New York Filed July 17, 1961, Ser. No. 124,446 3 Claims. (Cl. 260-632) This invention relates to new acyclic primary alcohols and processes for making same from cis and transmyrtanol.

The cis and trans-myrtanol may be prepared from pinene by hydroboration followed by oxidation, in accordance with I. C. Braun and G. S. Fisher, Tetrahedron Letters, No. 21, pp. 9-11, 1960, and references therein. An alternate synthesis via aluminum alkyl exchange with IB- pinene also provides a convenient method of preparation, following the general procedure in the following authors: K. Ziegler, F. Krupp and K. Zosel in Annalen der Chemie, vol. 629, pp. 241-250, of 1960.

The principal object of the invention is to produce primary acyclic alcohols of the type described, and to provide a simple, efficient process for their manufacture.

I have found in accordance with my invention that such alcohols may be produced by pyrolytic isomerization of cis and trans-myrtanols, and that such alcohols are valuable perfume materials.

The invention comprises the novel products as well as the novel processes and steps of processes according to which such products are manufactured, the specic embodiments of which are described hereinafter by way of example and in accordance with which I now prefer t practice the invention.

I have found that myrtanol, either as the cis or transisomer, when heated to pyrolysis temperatures in the vapor-phase yields a mixture of the following: (1) [6- methyl-Z-vinyl S-heptene-l-ol] and (2) [2-(2-rnethyl propenyl) hexene 1 ol], and (3) unreacted myrtanol, formed in accordance with the following reactions:

The alcohols formed, (l) and (2), possess a degree of optical activity which is dependent upon the optical activity of the myrtanol used. In general I have found it important to conduct the isomerization in the vaporphase, the temperature ranging from at least 450 to 825 C., under reduced pressure, preferably 20 mm. Hg. I have found, furthermore, that the pyrolysate may be separated into its constituents by vacuum fractional distillation.

The following are examples of the manner in which I now prefer to carry out my invention for the produc- Mice tion of the products mentioned. It is to be understood that the invention is not to be considered as limited thereto except as indicated in the appended claims:

Example 1.--400 grams of cis-myrtanol, boiling point C./0.5 mm. Hg, 111320 1.4887, D425 0.970, [a]23D -17.01 C.; pertinent infrared bands,

1047 cm.1 (C-O stretch) were pyrolyzed in a 27 stainless steel tube, type 310, 1A" O.D., at 20 mm. Hg at 750- 825 C. with a throughput of 100 gms/hr. The temperature was determined by a thermocouple inserted in the tube. An ordinary water-cooled condenser was used at the exit of the pyrolysis tube, and the pyrolysate passed through it and was collected.

Distillation of the pyrolysate, so obtained, through a 3 ft. spiral tantalum column gave a constant boiling fraction, 260 gms., boiling point 60 C./ 0.5 mm. Hg, to produce two components as determined by VPC (vaporphase chromatography). The two components of this fraction were separated by fractional distillation using a Piros-Glover spinning band column; their purity was established by VPC analysis.

Component 1.-[6methyl2vinyl S-heptene-l-ol] had the following properties: boiling point 69.5-70.5 C./4 mm. Hg; nD20 1.4666, [a]24D +8.30". Pertinent infrared data:

liq.

vmx. 3320 om.'1 (hydroxyl) liq.

um 3820 om.1 (hydroxyl) 995 cm.-1 and 911 cm.-1 (vinyl methylene); 848 cm.1 (isopropylidene), as shown in FIGURE 2 described below. It appears that the methyl alpha to the isopropylidene is responsible for displacements to higher frequencies than normally observed for the isopropylidene residue.

This component weighed 144 gms., giving a yield of 36% of [2-(2-methyl propenyl)5hexene1ol].

The residue consists of unreacted myrtanol.

The mixture of components 1 and 2 has a sweet, soft oral odor like the linalool family, but more earthy green. It is useful in hyacinth and violet-narcisse perfume compositions.

Example 2.--Trans-myrtanol, when pyrolyzed under similar conditions, gave an overall conversion of 55% of the aforementioned components. This conversion, however, produced more of component 1, 30%, than of component 2, 25%.

In general, the yields of the desired alcohols increase with increasing temperature, and the conversoin is greatest at 775-825 C.; incipient formation of components 1 and 2 occurs at 450 C. The recovered, unreacted myrtanol which is easily separated from the products by distillation may be recycled; since dehydration of myrtanol is negligible under the conditions described the conversion can be increased to by recycling. Alternatively, increasing the residence time in the pyrolysis tube by increasing tube length also increases the conversion.

In the -accompanying drawing forming part of this application:

FIGURE 1| is an infrared spectrum of 6-methyl-2-vinyl- S-heptene-l-ol, and

FIGURE 2 is an infrared spectrum of 2-(2-methyl-propenyU-S-heXene-l-ol.

3 v 4 I Ielaim: References Cited by the Examiner 1. An acyclic alcohol selected from the group consist- UNITED STATES PATENTS ing of compounds having the following formulae: 2 453 110 11/1948 Bain et al 260 632 CIHZOH H2 5 2,801266 7/1957 schinz 26o-631.5 /g\ o\ 2,972,632 2/1961 Bain et al. 260-63L5 H2? (KH IMI/ (um 2,972,633 2/1961 Klem 26o- 631.5 Ho\ CH2 and CHoH-Ho\ CH2 FOREIGN PATENTS IIH WH 10 1,150,974 7/1963 Germany. K /C\ OTHER REFERENCES C 3 CH3 CH3 CH3 Bietstein: vol. 1, 3rd Sup. (1958), page 2014. 2. [6-methyl-2-v1nyl S-heptene-l-ol] hoavlng the follow' Heusler etal.: Chemistry of Terpenes, page 383 (1902). mg properties: borlmg polnt 69.5-70.5 C /4 mm. Hg; 15 Schinz: Chem. Abst VOL 41 (1947) page 1392 nD2 1.4666, [0:]24D +8.30', and having the infrared spfztrllzritl(howrll1 1FIGURE 1.1) 5 h 1 h LEON ZITVER, Primary Examiner.

-met y- -propen-l-y exene-l o] aving the following properties: boiling point 66 C./ 4 mm. Hg, CHARLES B' PARKER Exammer nD20 1.4654, [a]24D +1334", and having the infrared 2 A. H. SUTTO, M. B. ROBERTO, J. E. EVANS, spectrum shown in FIGURE 2. 0 Assistant Examiners. 

1. AN ACYCLIC ALCOHOL SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS HAVING THE FOLLOWING FORMULAE: 